Sony is working on PlayStation 4

Sony has confirmed that work on a "future platform" to follow the PS3 "is already under way".

Sony's executive vice president and chief financial officer Masaru Kato made the revelation on a conference call to investors today. He was asked to explain increased research and development (R&D) costs.

"For the home equipment the PS3 still has a product life," he said, "but this is a platform business, so for the future platform - when we'll be introducing what product I cannot discuss that - but our development work is already under way, so the costs are incurred there."

Kato's comments are in direct contrast those of Sony Computer Entertainment boss Kaz Hirai's. Hirai said, three months ago in March, that "a near-future PS4 or next-generation home console is not something that we are even debating now".